You left off as many of the external details as possible before painting? I'm in the planning process on a diorama that's going to incorporate 1/35 models from several sources -- a pair of flatcars spotted on a siding offloading mecha (Gasaraki/Border Break size) with a tank on overwatch while the mecha pilots get things sorted out, and I want to do both the tank and the mecha in digicam. However, in the 'how-to' guides I've found, whether for soft-edge or hard-edge camo, almost all of them have the models built up with all the external gear -- shovels, jacks, tow chains, etc. -- before painting, and I'm unconvinced that I'm going to be able to get good masking trying to wrap tape around external equipment.